Field of Technology
The embodiments herein relate to a display device, and more particularly, to a display device with an integrated in-cell type touch screen and a driving method thereof.
Discussion of the Related Art
Touch screens are a type of input device that is included in display devices such as liquid crystal display (LCD) devices, field emission displays (FEDs), plasma display panels (PDPs), electroluminescent displays (ELDs), and electrophoretic displays (EPDs), and enable a user to input information by directly touching a screen with a finger, a pen or the like while looking at the screen of the display device.
Particularly, the demand for display devices with integrated in-cell type touch screen, which include a plurality of built-in elements configuring the touch screen for slimming portable terminals such as smart phones and tablet personal computers (PCs), is recently increasing.
In a related art display device with integrated in-cell type touch screen disclosed in U.S. Pat. No. 7,859,521, a plurality of common electrodes for display are segmented into a plurality of touch driving areas and touch sensing areas, thereby allowing a mutual capacitance to be generated between the touch driving area and the touch sensing area. Therefore, the related art display device measures a mutual capacitance change that occurs in touch, and thus determines whether there is a touch.
In the display device with an integrated in-cell type touch screen, in order for each of a common electrode to perform a function of a touch electrode, when a panel operates in a touch driving mode, a driving pulse is applied to common electrodes corresponding to a touch driving area and whether there is a touch is determined by using a plurality of sensing signals from common electrodes corresponding to a touch sensing area.
Moreover, the common electrodes corresponding to the touch driving area and the common electrodes corresponding to the touch sensing area overlap a corresponding data line. When the panel operates in a display driving mode, a data voltage is applied to a data line, and when the panel operates in the touch sensing mode, voltages in the same state are respectively applied to data lines.
When the panel operates in the touch driving mode, since voltages in the same state are respectively applied to data lines, parasitic capacitance increases, or a voltage of a data line is affected by the driving pulse. For this reason, a mutual capacitance error occurs, causing a reduction in touch performance.